1. Field of the Invention
The present invention relates to a push button lock which includes a mechanism and its components assembled in a cartridge for setting and storing a security code for locking and unlocking. The cartridge is detachably attached in a housing so that various designs are available on the surface of the housing. The lock is manufactured and designed in an efficient manner, and requires less maintenance, thereby facilitating mass production. The security code for the lock is easily and readily set or altered with the lock attached to a door and without using a tool. The lock has an increased protection function, thereby improving convenience and safety. Further, a streamlined design of the push button lock reduces the load applied to a lock pin, prevents damage by tampering and erroneously pushing the push buttons, and thereby enhancing safety in use and increasing productivity.
2. Description of the Related Art
Recently, keyless locks are widely used for doors of houses, stations, stores, and hospitals. One such keyless lock is a mechanical lock, which is locked and unlocked by a mechanical manner, requires no wiring, and there is no worry about a power outage and power source, as opposed to the electric lock, which is operated by an electrical manner. The mechanical lock has increased security function and requires less maintenance. Due to high mechanical strength, the demand is increasing.
The mechanical lock is installed at a door, a case frame of the mechanical lock comprises a plurality of push buttons for programming a security number, and a door handle. A dead bolt lock is provided inside the door. The lock is locked and unlocked by the deadbolt which moves in accordance with operation of the push buttons. One mechanical lock is provided inside with a plate-like block on the surface of a case frame, and a plurality of plate bodies is laminated inside the case frame. Each plate body is provided with a plurality of slits or through holes. A substantially S-shaped and plate-like button having a slit is inserted in the slits or through holes, with the button upright or inverted. Then, a security number is entered by setting the push button at a memory or non-memory state (refer, for example, to patent documents 1 and 2).
However, the mechanical lock has following problems. In order to set or alter the security number, the block and the case frame need to be detached to uncover the button. Further, adjacent components needs to be disassembled to change the orientation of the buttons either upright or inverted, and then buttons are inserted in the slits of the plate body again. This operation causes trouble because the upright and inverted states of the button are very similar and confusing. Each plate body is laminated in sequence in the case frame and integrally attached to each other. Thus, the case frame and the plate bodies cannot be separated, and making efficient, mass production difficult. The size and shape of each component is restricted, such that the design of the case frame is limited.
In order to solve the above-described problems, other such mechanical lock includes a plurality of slide plates laminated inside the case frame, and a plurality of slits or holes are formed on the slide plates. A push button provided with a plurality of notches on the shaft periphery is inserted in the slits or holes. The notch, the end portion of the push button, is provided to appear on the back side of the door. A screwdriver is engaged with the notch and turned in either direction. A security number is entered by setting the push button in a memory state or non-memory state (refer, for example, to patent documents 3 and 4).
In the above-described mechanical lock, the components do not need to be detached when setting or altering the security number and the operation becomes easier, however, there are following problems. Use of tools, such as a screwdriver is required. Further, each plate body is laminated in sequence in the case frame, such that efficient and mass production is difficult. The size and shape of each component is restricted, such that the design of the case frame is limited. Further, the complicated structure of the button makes manufacturing difficult.
Further, when the mechanical lock is unlocked, the position of the push button is parallel to the slit and then a key plate is movable. After engagement between the cam pin and the plate is released, the door handle is turned. Thus, there is a danger of bending or damage of the push button because the incorrect push button is engaged with the key plate when the push button is not pressed correctly and further the door handle is turned by, for example, tampering. If stronger material is employed for the push button as a means to solve the above-described problem, the material costs would increase and the productivity would decrease.
Other such mechanical lock includes a plurality of buttons on the surface of the case for entering a security code, a hole provided near the button for inserting an operational tool, a button gear provided inside the case and being rotatable when the button is operated, a terminal gear engageable with the button gear, and a reset gear engageable with the terminal gear. When the security number is set or altered, the operational tool is inserted in the hole, and then corresponding button is pressed given times (refer, for example, to patent document 5).
The above-described mechanical lock reduces trouble in operation, such as detaching the components when setting or altering the security number, however, use of tools is required. Further, each plate body is laminated in sequence in the case frame, making efficient and mass production difficult. Additionally, size and shape of each component is restricted, such that the design of the case is limited.